Which substance is most commonly used for marking in metalwork?

Soapstone is the most commonly used substance for marking in metalwork due to its unique properties that make it ideal for this application. It is a soft, talc-based mineral that can be easily shaped into marking sticks. Soapstone produces a clear and visible line when applied to metal surfaces, ensuring precise markings for cutting or fabrication. Additionally, it burns off during the welding process, which is advantageous as it prevents contamination of the weld area.

In contrast, while pencils can be used for marking, their marks may not always be easily visible on shiny metal surfaces and can be removed too easily. Chalk does not adhere well to metals, making it less effective for long-lasting marks in a metalworking environment. Paint, while useful for various applications, is typically not practical for marking as it can add unwanted thickness and requires drying time, which can interfere with immediate tasks. Thus, soapstone stands out as the preferred choice for clarity, ease of use, and compatibility with metalworking processes.